The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In the case of enhanced exhaust regulations such as RDE (Real Driving Emission), which was applied in September 2017, vehicle test conditions became more extreme at outside temperatures of −7˜35° C. Accordingly, researches on exhaust gas and fuel consumption in low temperature of intake air/high temperature of intake air, which are flowed into an engine combustion chamber, are being conducted.
When the intake air temperature is very low, the NOx emission is increased due to the limitation of the exhaust gas recirculation (EGR) supply, and when the intake air temperature is high, the NOx emission amount is increased due to the increase of the combustion temperature.
Thus, there is a need for improvements in the cooling system that cools the engine and the various systems to accommodate enhanced exhaust emissions regulations.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.